Corner-lock carton



June 5, 1962 R. J. HICKIN CORNER-LOCK CARTON Filed July 29, 1960 IN VENTOR United States Patent 3,037,680 CORNER-LOCK CARTON Robert J. Hickin,Seville, Ohio, assignor to Packaging Corporation of America, Rittman,Ohio, a corporation of Delaware Filed July 29, 1960, Ser. No. 46,158Claims. (Cl. 229-435) This invention relates to cartons made from blanksof foldable sheet material such as paperboard, and it has referenceparticularly to cartons of the corner-lock type in which the matingedges of adjacent carton walls at the carton corners are joined inerected position by cooperating catches or hook members carried by oneof such walls and slit means in the other wall, all as is well known inthe carton art.

Ordinarily the catches or hook members are carried at the free edges offlaps hinged to one of the walls of the corner-forming pairs, and theseflaps are disposed exteriorly of the other walls of the pairs with theircatches inserted inwardly through the slit means of such other walls,but in some cases the flaps may be disposed interiorly with theircatches passing outwardly through the slit means and hence disposedexteriorly of the other walls.

In paperboard cartons, to the production of which this invention isprimarily directed, the characteristics of the material are such, due tolack of adequate rigidity, thickness or caliper, tear strength and thelike, that the corner lock provided by the hook or catch and slitconnection fails when the carton, particularly if loaded, is notcarefully handled, by disengagement of the hook or catch from the slitmeans.

One object of the invention is to so improve the corner lock means thatits failure will be guarded against.

Another object is to attain this desired improvement in a simple mannerand without adding to the cost of the cartons.

A further object is to attain this desired object by means integral withthe carton blank and produced in the blank during the blank-formingprocess.

Other objects and advantages of the invention will be apparent from thefollowing description.

Broadly considered, the invention comprises the provision upon the hookor catch members of the corner locks of bosses which extend to theiredges that engage the complemental edges of the slits, thus, in efleot,serving to increase the effective thickness of these edges in the zonesof their cooperative engagement with the edges of the slits; and thesaid bosses may be, and preferably are, formed by a simple embossingoperation such as may be performed with an ordinary creasing rule orscore-forming tool, all as will be explained more in detail hereinafterand finally claimed.

In the accompanying drawing illustrating the invention, in the severalfigures of which like parts are similarly designated,

FIG. 1 is a plan view of the inner face of a carton blank embodying theinvention,

FIG. 2 is an enlarged fragmentary section taken on the line 2--2 of FIG.1, and

FIG. 3 is an enlarged fragmentary perspective view showing one end ofthe blank of FIG. 1 in erected condition.

'I he carton blank shown in FIG. 1 is more or less conventional, broadlyconsidered, as related to cornerlock cartons or trays, and comprises abase, or bottom, panel member 1, side wall members 2 defined from thebase panel member 1 by folding scores 3, and end wall members 4 definedfrom the base panel member by folding scores 5.

3,037,680 Patented June 5, 1962 'ice The opposite edges of the end wallmembers 4 are provided with flaps 6 foldable on hinge scores 7, andthese flaps carry at their free edges the hooks or catch members 8adapted, upon erection of the carton, to be engaged with the side wallmembers 2 by insertion through and engagement with the slit means 9--10of these wall members.

In accordance with the invention the hooks or catch members 8 areprovided with transverse bosses 11 which intersect their perimeters attwo spaced locations and extend substantially vertically of them when inerected condition and serve, due to the fact that they offstand from theplane of the blank, to provide offsets which increase the eifectivethickness of the flaps particularly in the zones of their edges 8 whichengage the portions :10 of the slits 910. These bosses may be producedsimply and cheaply during the blank-forming process by the operation ofa conventional creasing rule or scoring tool as hereinbefore stated.

The carton or tray of the invention may be erected in the manner andwith mechanisms conventionally used in the setting-up of corner-lockcartons, whereby, when the side walls 2 have been erected, the end wallsare erected with their flaps 6 embracing the side walls and the hook orcatch means 8 inserted through the slit means 9-10 to effect lockingengagement of the parts.

Although, as shown particularly in FIGS. 1 and 3, the bosses 11 offstandinwardly from the inner faces of the hook or catch means 8, they may,particularly if the flaps 6 are disposed inwardly of the side wallmembers 2 as hereinbefore suggested, oifstand outwardly from the outerfaces of the hook or catch means 8, if desired.

In addition to their function in enhancing the locking engagement of thehook or catch and slit means of the corner lock, the bosses 11 extendinginwardly of the side walls will so space moist or greasy products packedin the carton from the edges of the books or catches and the edges ofthe slit means in the side walls as to prevent unsightly wicking ofmoisture or grease into these parts.

Various changes and modifications are considered to be within theprinciple of the invention and the scope of the following claims.

What I claim is:

l. A corner-lock carton, having a base panel member and a pair of wallmembers at a corner of said base panel member and olfstanding angularlyfrom said base panel member, a flap hinged to the corner-forming edge ofone of said wall members and cooperating with the other wall member toform said corner, said other wall member being provided with slit meansspaced from the corner-forming edge thereof, said flap being providedwith a catch member insertable through said slit means when said wallmembers are erected to corner-forming relation, said catch member havinga perimetral portion thereof abuttingly engaging an edge of said slitmeans to effect interlocking of said wall members at said corner, saidcatch member being provided with a transverse boss offstanding from theplane of the catch member and intersecting the perimeter thereof at twospaced locations to provide an offset in the zone of its abuttingengagement with said edge of the slit means,

2. A carton as defined in claim 1, in which said boss extends acrosssaid catch member in a direction substantially normal to said base panelmember.

3. A carton as defined in claim 1, in which said flap is disposedagainst the outer surface of said other wall member with said catchmember disposed against the inner surface thereof, the boss of saidcatch member offstanding therefrom inwardly of the carton wall.

4. In a corner-lock carton, having a base panel member, pairs of wallmembers otfstanding substantially normal to said panel member and havingtheir meeting end edges forming corners for the carton with the said endedges of the walls of said pairs joined by corner locking meanscomprising catch means carried by flaps hinged to the corner-formingedges of one wall of a pair and complemental slit means in the otherwall of the pair and spaced from the corner-forming edge thereof with anedge of the catch means abuttingly engaging a complemental edge of theslit means, the improvement which comprises boss means on said catchmeans extending transversely thereof and offstanding from the plane ofthe catch means and intersecting its perimeter at two spaced locationsto provide an offset in the Zone of its abutting engagement with saidedge of the slit means.

5. A blank for a corner-lock carton, comprising a sheet of foldablematerial provided with cuts and folding scores defining a base panelmember, side and end wall members foldably attached to said base panelmember at its borders and erectable substantially normal thereto withtheir end edges in juxtaposition at the corners of the base panelmember, and corner-lock means for said members including slit means inone of said wall members spaced from a corner-forming edge thereof andcatch means carried by a flap hinged to the corner-forming edge of theother wall member, said catch means having a perimetral edge and servingfor insertion through said slit means and for abutting lockingengagement with an edge thereof when said wall members are erected incorner-forming relation, said catch means being provided with atransverse boss otfstanding from the plane of the catch means andintersecting its perimetral edge at two spaced locations, said boss thusserving to provide an offset in the zone of abutting engagement of saidcatch means with the said edge of the slit means.

References Cited in the file of this patent UNITED STATES PATENTS1,652,251 Oliver Dec. 13, 1927 1,796,035 Maier Mar. 10, 1931 2,677,493Wanda May 4, 1954 2,901,158 Carpino Aug. 25, 1959

